A pendulum suspension device of a spray ramp on an agricultural machine is known from the prior art, typically comprising, as this is visible in FIGS. 1 to 3, a fixed frame 1 intended to be borne by an agricultural machine, a mobile frame 2 pendularly connected through a suspension connecting rod 3 to the chassis 1, and a correction actuation cylinder 4 interposed between the mobile frame 2 and the fixed frame 1.
The mobile frame 2 is intended to support spray ramps, one portion 5 of which supporting spray nozzles 6a, 6b, 6d is visible in the figures appended herein.
When the machine circulates on flat ground (see FIG. 3), the mobile frame 2 is parallel to the ground and therefore substantially perpendicular to the fixed frame 1.
When the machine circulates on sloping ground (see FIG. 4), the suspension point 7 and the center of gravity 8 of the mobile frame 2 tend to remain aligned on the vertical V, which in other words means that the spray ramp tends to keep a horizontal position.
The result of this is a relative tilt of the mobile frame 2 relatively to the fixed frame 1 and relatively to the ground S.
As it is sought to obtain homogeneous spraying, it is necessary to establish parallelism between the mobile frame 2, and therefore the spray ramps, and the ground S, so as to achieve the configuration illustrated in FIG. 5.
This configuration is obtained by acting on the actuation cylinder 4.
During this actuation, because the center of gravity 8 and the suspension point 7 of the mobile frame 2 tend to remain aligned along the vertical V, this center of gravity 8 moves away by a certain distance D from the middle line M of the fixed frame 1.
The result is therefore a lateral shift of the mobile frame 2, and of the associated spray ramps, relatively to this middle line M.
This is notably damaging since the result may be gaps or doubles in spraying during the following passages of the agricultural machine, it being noted that successive passages are preferably separated by a constant distance.